This invention relates to process and apparatus for continually producing fire logs of the type comprised of sawdust held together with a wax binder. Particularly, this invention relates to such a process which is continuous and includes a continuous cooler for treating the hot sawdust-wax mixture to obtain a proper consistency prior to forming in an extruder.
Currently, large numbers of fire logs are on the market intended for home use. These manufactured fire logs are typical fire log size and shape and have advantages over natural wood logs. One advantage is the long burning nature of these manufactured logs which eliminates the necessity of frequent feeding of the fire. Also, less storage space is required, since only a single log is required for a period of burning of perhaps three hours. Further, fire enhancing chemicals can be added to the logs which produce the desirable coloration of flame, especially in the blue and green areas which are not found in natural wood logs. Another advantage of these manufactured fire logs is that they utilize a waste product, sawdust, in their manufacture. Lumber mills and other operations that saw wood produce great quantities of sawdust which otherwise is merely incinerated to eliminate the disposal problem. However, with the advent of the manufactured fire logs this sawdust liability has turned into a sawdust asset.
In manufacturing fire logs from sawdust the conventional process is to combine sawdust with hot wax in a mixer to produce a hot product. However, this hot product cannot be formed or extruded into the fire log shape in its hot condition. Accordingly, the practice has arisen wherein the hot product is placed into large bins and trucked away from the mixer by use of the fork lift trucks, etc., to a storage yard. In the storage yard ambient cooling of the hot mixture occurs over a time. After the mixture has cooled, it is then taken to the extruder where it is fed therein to produce the fire log shape. This batch processing of the prior art has had serious disadvantages. For instance, it is quite costly in terms of time and money to have to individually bin the hot mixture and transport it to the cooling yards. Also, the texture and consistency of the mixture is not completely controllable since it is subject to the vagaries of the ambient surrounds. Further, wasted energy is involved in the transportation of the bins which has to be accomplished both from and to the plant.
It is to a solution of these and other problems that this invention is directed.